feat(website): add SEO landing pages for Claude Code, Codex, and OpenCode

Extract homepage into reusable LandingPage component with configurable
hero. Add /claude-code, /codex, and /opencode routes targeting
agent-specific mobile app search terms. Replace single-link footer
with four-column layout (Product, Agents, Community, Download).

packages/website/src/routes/opencode.tsx

@@ -0,0 +1,25 @@
+import { createFileRoute } from '@tanstack/react-router'
+import { LandingPage } from '~/components/landing-page'
+
+export const Route = createFileRoute('/opencode')({
+  head: () => ({
+    meta: [
+      { title: 'OpenCode Mobile App – Code from anywhere | Paseo' },
+      {
+        name: 'description',
+        content:
+          'Run OpenCode from your phone. Launch agents, watch them work, and ship code from wherever you are. Self-hosted, open source, your code stays local.',
+      },
+    ],
+  }),
+  component: OpenCodePage,
+})
+
+function OpenCodePage() {
+  return (
+    <LandingPage
+      title="Run OpenCode from your phone"
+      subtitle="Launch agents, check on builds, and ship code from anywhere. Same setup, same machine, just not at your desk."
+    />
+  )
+}